1. Field of the Invention
This invention generally relates to a synchronizing system and particularly to a system for synchronizing two or more process units, such as filling and capping units arranged in a bottle handling line.
2. Description of the Prior Art
Various process units are arranged in a container handling line which handles containers, such as bottles. Typical process units include a filling unit for filling desired contents, such as beverage, into containers by a predetermined quantity and a capping unit disposed downstream of the filling unit for capping the containers thus filled with the desired contents. Since the containers are transported along a predetermined travelling path through the filling and capping units continuously, the filling and capping units must be operated synchronously. In accordance with the typical prior art structure, use was made of a common driving shaft thereby mechanically coupling the filling and capping units.
FIG. 1 shows part of the typical prior art container handling system, which includes a filling unit 1 for filling contents into containers, such as bottles, and a capping unit 2 for capping the containers after having been filled with the contents. As shown, the filling unit 1 includes a center column 1a which is fixedly mounted on a turntable 27 (see FIG. 2) and thus is driven to rotate in a predetermined direction. On top of the column 1a is fixedly mounted a filling head 1b along the periphery of which are provided a plurality of actuator cylinders 1c, each of which is provided with a projectable rod 1d having a filling nozzle 1e mounted at its bottom end. Also provided is a pair of timing screws 3a and 3b which are driven to rotate synchronously with the filling and capping units 1 and 2 as will be described more in detail later. As the timing screws 3a and 3b are driven to rotate in a predetermined direction, containers B such as bottles are transported as engaged with a spiral groove engraved therealong, as shown in FIG. 2. Thus, the containers B are transported as spaced from one another at a predetermined pitch.
As also shown in FIG. 2, an inlet star wheel 25 provided with a plurality of notches along its periphery is disposed at the downstream end of the timing screw 3a for receiving the containers B transported between the timing screw 3a and a guide plate 24 and having them transported to the turntable 27 as guided by a guide rail 26 and the star wheel 25. Although not shown specifically, as well known for one skilled in the art, the turntable 27 is typically provided with container holding units mounted along its periphery, and, thus, the containers B are temporarily securely held on the turntable 27 thereby being transported along the path indicated by the two-dotted line. While the containers B are securely held as described above, the filling nozzles 1e are moved downward to engage with the mouths of the containers B thereby having desired contents filled into the containers B by a predetermined amount.
Also provided is an outlet star wheel 28 between the turntable 27 and the timing screw 3b, as shown in FIG. 2. The outlet star wheel 28 is driven to rotate counterclockwise also synchronously so that the containers B now filled with the desired contents are transported along a guide rail 29 to be brought into engagement with the timing screw 3b which extends between the filling unit 1 and the capping unit 2. Also provided is a guide plate 30 which extends in parallel with the timing screw 3b thereby defining the travelling path for the containers B between the filling and capping units 1 and 2. At the downstream end of the timing screw 3b is disposed the capping unit 2 which includes a center column 2a, a capping head 2b fixedly mounted on top of the center column 2a, a plurality of vertically movable rods 2c arranged along the periphery of the head 2b and a like plurality of capping blocks 2d, each mounted at the bottom end of the corresponding rod 2c. Similarly with the filling unit 1, the capping unit 2 also includes a turntable (not shown), which is driven to rotate synchronously with the timing screw 3b. Thus, while the containers B filled with desired contents move along a predetermined circular path as riding on the turntable after having been transported from the timing screw, the capping blocks 2d are lowered to be brought into engagement with the mouths of the containers B to have them capped.
FIG. 1 also shows a driving system for driving the filling and capping units 1 and 2 and the timing screws 3a and 3b synchronously. As shown, there is provided a driving motor 22 whose driving force is transmitted to the filling unit 1 through a driving shaft 23a and further through driving shafts 23b and 23c to the timing screws 3a and 3b. On the other hand, the driving motor 22 also transmits its driving force to the capping unit 2 through power transmitting elements 23d, 23e, 23f and 23g. Such a synchronized driving system tends to be bulky and complicated in structure. Moreover, the driving motor 22 must be large in capacity, which tends to push up the cost. Further, since it is entirely mechanical structurally, it requires extensive care and maintenance and lacks adaptability to different operating conditions. Also shown in FIG. 1 are control panels 20 and 21 for controlling the operation of the filling and capping units 1 and 2, respectively.